Method and apparatus for rolling



J y 7. A. B; MONTGOMERY 2,087,065

METHOD AND A PPARATUS FOR ROLLING Filed Jan. 19, 1934 II III] INVENTOR Patented July, 13, 1937 Q i UNITED STATES PATENT OFFICE un'rnon' ANnArrnaA'rUs FOR ROLLING Alonzo B. Montgomery, Youngstown, Ohio, 'assignor to The Cold Metal Process Company, Youngstown, Ohio, a corporation of Ohio I Application January 19', 1934, Serial No. 707,401

Claims.

My invention relates tothe rolling of metal and particularly to long lengths of thin sheet metal,

such as strip". v

In the U. S. patent granted July 18, 1933 to 5 Keeney, et al., No. 1,918,968, there is disclosed a four-high reversing mill with heating furnaces on opposite sides thereof for hot rolling strip.

My invention is concerned chiefly with improvemerits upon the method and apparatus disclosed in said patent.

For certain classes of product, it is desirable to provide a finish on the hot strip superior to that which can be obtained with the mill shown in the Keeney patent, in which the entire reduction from the slab to the strip is effected by the same rolls. In order to roll a slab in the Keeney mill, the slab must behighly heated, specifically,

, above the temperature at which free scaling occurs. The presence of the scale on the slab roughens the rolls and precludes the obtaining of a high finish on the hot strip of final gauge.

The rolls thus wear rapidly and require frequent changing. The output, furthermore, is limited because of the fact that the slabbing operation is necessarily slow due to the frequent reversals of the mill, and full advantage of the capacity of the four-high mill for high-speed operation is realized only during a portion of the operating cycle, namely, during the rolling with coiling.

In rolling strip from slabs on the Keeney mill, in addition, the effect of the edging rolls used to control and assist in the removal of scale, is to .cause the production of ears or projections at the corners of the slab as it is reduced to strip form. These ears make itdifllcult to direct mahot rolling.

In accordance with my invention, I take a slab after it has been properly heated in a suitable 40 furnace and subject it to repeated passes through a universal mill to elongate it considerably with- .out materially increasing its width. The ends of the piece are then sheared off to remove the ears projecting therefrom. The material is then passed into another reversing mill, c. g., that of the Keeney patent, with heating furnaces on opposite sides thereof, where it is subjected to further rolling with coiling between passes. After the material has been reduced sufficiently in the 50 four-high mill, it is wound on a final coiler. p For a complete understanding of the invention, reference is made to the accompanying drawing illustrating diagrammatically a present preferred embodiment of the invention and the method of 55 its practice.

terial on to the coiler for the continuation of the Referringv in detail to the drawing, furnaces II! are provided forv heating slabs for delivery to a universal mill 1 i. As is well known, the universal mill is a two-high reversing mill with one or more pairs of vertical rolls or edgers. A roll table I2 I extends from the furnaces to the mill. A slab shear i3 is positioned at a suitable distance ahead of the mill II with a connecting roll table l4 therebetween.

A second reversing mill l5, preferably but not 10 necessarily a four-high mill, has coil-heating furnaces l6 and I1 on opposite sides thereof, and pinch rolls I8 between the, coil furnaces and the mill rolls. A roll table i9 connects the shear l3 and the mill l5. A crop conveyor 20 and a slab ll conveyor 2|, with an associated pusher 22, extends laterally from the table I9. A hot strip coiler 24v is located beyond the mill l5. Roll tables 25 connect the mill l5 and the coiler 24.

The operation of the apparatus above enumero ated to perform the method of my invention, may be described briefly as follows: The slabs are fed into the furnaces ill to be heated prior to rolling in the mill II. The slabs are initially 2" to 14" thick and of suitable width and length to 25 provide the desired dimensions of finished hot strip. The heated'slabs are passed back and forth through the universal mill'ii, which effects a slabbing operation, until the slab is reduced to a thickness of or less, with a corresponding elongation, and is cooled to a point where free scaling substantially ceases. The partially reduced slab is then forwarded to the four-high mill IS. The ends of the hot slab, however, are sheared off by the shear l3 before the piece arrives at the coiling mill.

Generally, I prefer to perform all slabbing operations on the mill II and thereby reduce the material to a gauge suitable for coiling before advancing it to the mill Hi. The material enters the mill 15 while still hot and is coiled up in the coilheating furnace l1 after the first pass through the mill. 0n the next pass, the material is coiled in the heating furnace It. This cycle is repeated and the partially reduced slab is gradually elongated to strip form, the heat lost from the strip by radiation, and otherwise, being supplied I during the interval it dwells in the coil-heating furnaces.

When the strip has been reduced to final gauge, ay .065", it is advanced from the mill [5 in the flat form along the table 25 toward the final coiler 24. After the strip has been coiled on the coiler 24, and cooled, it is ready for shipment 55 or further processing, for example, by cold roll ing.

While I have stated that it is preferable to perform all the slabbing operations on the mill II, it is possible that in certain cases it may be desirable to effect some reduction of the material in the flat on the mill l5.

It will be apparent to those skilled in the artthat the invention described is characterized by numerous advantages over the practice and apparatus heretofore employed. In the first place, a higher finish can be obtained than by using the four-high mill for both slabbing and coiling operations. Since the slabbing operation is confined to the universal mill, by far the greatest portion of free scaling has occurred before the material reaches the four-high mill, at which time it is characterized by a tight, thin layer of oxide which adheres to the strip throughout the further rolling. Excessive accumulation of scale in the four-high mill is thus prevented, as well as the resulting injury to the surface of the working rolls. The output of the four-high mill is increased from 25 to 30%, furthermore, because of the fact that it is operating at high speeds a greater portion of the time than when slabbing operations are effected therein. The high speeds of which the mill is capable, of course, can best be taken advantage of when rolling the longer lengths. The reduction in the wear on the rolls of the four-high mill makes it unnecessary to change rolls as frequently as has heretofore been the case. The shearing of the ends of the partly reduced slab before rolling, greatly facilitates the entry of the material into the furnace reels, making the operation of the mill l5 more efiicient and avoiding the delays and loss of material incident to repeated efiforts to cause the end of the piece to engage the reel. While I have described the cropping of the ends of the slab as taking place between the slabbing and the rolling with coiling, it is obvious that where some slabbing is done on the four-high mill, the shearing may be performed after such final slabbing.

Although I have illustrated and described but a single preferred embodiment of my invention with certain possible modifications thereof, it will be understood that numerous changes in the apparatusand practice disclosed may be made without departing from the spirit of my invention or the scope of the appended claims.

I claim:

1. In a method of rolling metal strip, the steps consisting in supplying to a roughing mill a heated slab-like body which is too thick for coiling, rolling the body in the roughing mill until it is substantially thin enough to permit of coiling, but maintaining the thinned body in the flat state, and, in the same heat, feeding the thinned body to a reversing mill, subjecting it to successive passes therein to reduce it to a desired strip thickness, and coiling it between passes in the reversing mill.

2. In a method of rolling metal strip, the steps consisting in supplying to a roughing mill a heated slab-like body which is too thick for coiling, rolling the body in the roughing mill until it is substantially thin enough to permit of coiling, but maintaining the thinned body in the flat state, trueing the edges in said mill, and, in the same heat, feeding the thinned body to a reversing mill, subjecting it to successive passes therein to reduce it to a desired strip thickness, and coiling it between passes in the reversing mill.

3. In a method of rolling metal strip, the steps consisting in supplying to a roughing mill a heated slab-like body which is too thick for coiling, rolling the body back and forth in the roughing mill until it is substantially thin enough to permit of coiling, but maintaining the thinned body in the flat state, and, in the same heat, feeding the thinned body to a reversing mill, subjecting it to successive passes therein to reduce it to a desired strip thickness, and coiling it between passes in the reversing mill.

4. In a method of rolling metal strip, the steps consisting in supplying to a roughing mill a heated slab-like body which is too thick for coiling, rolling the body in the roughing mill until the body cools to a temperature below that at which free scale forms, and until it is substantially thin enough to permit of coiling, but maintaining the thinned body in the fiat state, and, in the same heat, feeding the thinned body to a reversing mill, subjecting it to successive passes therein to reduce it to a desired strip thickness, and coiling it between passes in the reversing mill.

5. In a method of rolling metal strip, the steps consisting in supplying to a roughing mill a heated slab-like body which is too thick for coiling, rolling the body in the roughing mill until it is substantially thin enough to permit of coiling, but maintaining the thinned body in the flat state, and, in the same heat, feeding the thinned body to a reversing mill after cropping at least one end of the thinned body to facilitate its entry into said reversing mill, subjecting it to successive passes therein to reduce it to a desired strip thickness, and coiling it between passes in the reversing mill.

ALONZO B. MONTGOMERY. 

